power: supply: test_power: add missing newlines when printing parameters by sysfs

[ Upstream commit c07fa6c1631333f02750cf59f22b615d768b4d8f ]

When I cat some module parameters by sysfs, it displays as follows.
It's better to add a newline for easy reading.

root@syzkaller:~# cd /sys/module/test_power/parameters/
root@syzkaller:/sys/module/test_power/parameters# cat ac_online
onroot@syzkaller:/sys/module/test_power/parameters# cat battery_present
trueroot@syzkaller:/sys/module/test_power/parameters# cat battery_health
goodroot@syzkaller:/sys/module/test_power/parameters# cat battery_status
dischargingroot@syzkaller:/sys/module/test_power/parameters# cat battery_technology
LIONroot@syzkaller:/sys/module/test_power/parameters# cat usb_online
onroot@syzkaller:/sys/module/test_power/parameters#

Signed-off-by: Xiongfeng Wang <wangxiongfeng2@huawei.com>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

drivers/power/supply/test_power.c

@@ -344,6 +344,7 @@ static int param_set_ac_online(const char *key, const struct kernel_param *kp)
 static int param_get_ac_online(char *buffer, const struct kernel_param *kp)
 {
 	strcpy(buffer, map_get_key(map_ac_online, ac_online, "unknown"));
+	strcat(buffer, "\n");
 	return strlen(buffer);
 }
 
@@ -357,6 +358,7 @@ static int param_set_usb_online(const char *key, const struct kernel_param *kp)
 static int param_get_usb_online(char *buffer, const struct kernel_param *kp)
 {
 	strcpy(buffer, map_get_key(map_ac_online, usb_online, "unknown"));
+	strcat(buffer, "\n");
 	return strlen(buffer);
 }
 
@@ -371,6 +373,7 @@ static int param_set_battery_status(const char *key,
 static int param_get_battery_status(char *buffer, const struct kernel_param *kp)
 {
 	strcpy(buffer, map_get_key(map_status, battery_status, "unknown"));
+	strcat(buffer, "\n");
 	return strlen(buffer);
 }
 
@@ -385,6 +388,7 @@ static int param_set_battery_health(const char *key,
 static int param_get_battery_health(char *buffer, const struct kernel_param *kp)
 {
 	strcpy(buffer, map_get_key(map_health, battery_health, "unknown"));
+	strcat(buffer, "\n");
 	return strlen(buffer);
 }
 
@@ -400,6 +404,7 @@ static int param_get_battery_present(char *buffer,
 					const struct kernel_param *kp)
 {
 	strcpy(buffer, map_get_key(map_present, battery_present, "unknown"));
+	strcat(buffer, "\n");
 	return strlen(buffer);
 }
 
@@ -417,6 +422,7 @@ static int param_get_battery_technology(char *buffer,
 {
 	strcpy(buffer,
 		map_get_key(map_technology, battery_technology, "unknown"));
+	strcat(buffer, "\n");
 	return strlen(buffer);
 }